How to create a custom SystemGroup?

I'm interested in updating some systems in a fixedupdate and I assume using a SystemGroup is the cleanest way of doing this. How do I create a custom system group?

Thanks.

https://forum.unity.com/threads/why-is-simulation-the-default-system-group.639058/

 

Code (CSharp):

1. [UpdateInGroup(typeof(InitializationSystemGroup))]
2. public class MySystemsGroupInOtherPlace : ComponentSystemGroup
3. {
4.    
5. }
6.  
7. [UpdateInGroup(typeof(MySystemsGroupInOtherPlace))]
8. public class TestSystem1 : JobComponentSystem
9. {
10.     protected override JobHandle OnUpdate(JobHandle inputDeps)
11.     {
12.         return inputDeps;
13.     }
14. }
15.  
16. //By default all groups and systems in SimulationSystemGroup
17. public class MySystemsGroupInSimulationGroup : ComponentSystemGroup
18. {
19.    
20. }
21.  
22. [UpdateInGroup(typeof(MySystemsGroupInSimulationGroup))]
23. public class TestSystem2 : JobComponentSystem
24. {
25.     protected override JobHandle OnUpdate(JobHandle inputDeps)
26.     {
27.         return inputDeps;
28.     }
29. }

 

!!!! Thanks. Exactly what I was looking for.

 

To have the SystemGroup update in FixedUpdate, you need to manually handle the PlayerLoop as SimulationSystemGroup is in the Update loop right now.

Code (CSharp):

1. public static void UpdatePlayerLoop(World world)
2. {
3.     var playerLoop = PlayerLoop.GetDefaultPlayerLoop();
4.     if (world != null)
5.     {
6.         // Insert the root-level systems into the appropriate PlayerLoopSystem subsystems:
7.         for (var i = 0; i < playerLoop.subSystemList.Length; ++i)
8.         {
9.             int subsystemListLength = playerLoop.subSystemList[i].subSystemList.Length;
10.             if (playerLoop.subSystemList[i].type == typeof(Update))
11.             {
12.                 var newSubsystemList = new PlayerLoopSystem[subsystemListLength + 1];
13.                 for (var j = 0; j < subsystemListLength; ++j)
14.                     newSubsystemList[j] = playerLoop.subSystemList[i].subSystemList[j];
15.                 InsertManagerIntoSubsystemList(newSubsystemList,
16.                     subsystemListLength + 0, world.GetOrCreateManager<SimulationSystemGroup>());
17.                 playerLoop.subSystemList[i].subSystemList = newSubsystemList;
18.             }
19.             else if (playerLoop.subSystemList[i].type == typeof(PreLateUpdate))
20.             {
21.                 var newSubsystemList = new PlayerLoopSystem[subsystemListLength + 1];
22.                 for (var j = 0; j < subsystemListLength; ++j)
23.                     newSubsystemList[j] = playerLoop.subSystemList[i].subSystemList[j];
24.                 InsertManagerIntoSubsystemList(newSubsystemList,
25.                     subsystemListLength + 0, world.GetOrCreateManager<PresentationSystemGroup>());
26.                 playerLoop.subSystemList[i].subSystemList = newSubsystemList;
27.             }
28.             else if (playerLoop.subSystemList[i].type == typeof(Initialization))
29.             {
30.                 var newSubsystemList = new PlayerLoopSystem[subsystemListLength + 1];
31.                 for (var j = 0; j < subsystemListLength; ++j)
32.                     newSubsystemList[j] = playerLoop.subSystemList[i].subSystemList[j];
33.                 InsertManagerIntoSubsystemList(newSubsystemList,
34.                     subsystemListLength + 0, world.GetOrCreateManager<InitializationSystemGroup>());
35.                 playerLoop.subSystemList[i].subSystemList = newSubsystemList;
36.             }
37.         }
38.     }
39.  
40.     PlayerLoop.SetPlayerLoop(playerLoop);
41.     currentPlayerLoop = playerLoop;
42. }

 

If you have multiple systems in a group would you use [UpdateInGroup(typeof(MySystemsGroup))] for all of your systems or just the first one (when also using UpdateAfter)?

 

All systems which should be in different from Simulation group - should use UpdateInGroup attribute